path: root/Software/Visual_Studio/Scripting/Tango.Scripting.Editors/Folding/FoldingSection.cs

// Copyright (c) AlphaSierraPapa for the SharpDevelop Team (for details please see \doc\copyright.txt)
// This code is distributed under the GNU LGPL (for details please see \doc\license.txt)

using System;
using System.Diagnostics;
using System.Text;
using System.Windows.Threading;
using Tango.Scripting.Editors.Document;
using Tango.Scripting.Editors.Rendering;
using Tango.Scripting.Editors.Utils;

namespace Tango.Scripting.Editors.Folding
{
	/// <summary>
	/// A section that can be folded.
	/// </summary>
	public sealed class FoldingSection : TextSegment
	{
		readonly FoldingManager manager;
		bool isFolded;
		internal CollapsedLineSection[] collapsedSections;
		string title;
		
		/// <summary>
		/// Gets/sets if the section is folded.
		/// </summary>
		public bool IsFolded {
			get { return isFolded; }
			set {
				if (isFolded != value) {
					isFolded = value;
					ValidateCollapsedLineSections(); // create/destroy CollapsedLineSection
						manager.Redraw(this);
				}
			}
		}
		
		internal void ValidateCollapsedLineSections()
		{
			if (!isFolded) {
				RemoveCollapsedLineSection();
				return;
			}
			// It is possible that StartOffset/EndOffset get set to invalid values via the property setters in TextSegment,
			// so we coerce those values into the valid range.
			DocumentLine startLine = manager.document.GetLineByOffset(StartOffset.CoerceValue(0, manager.document.TextLength));
			DocumentLine endLine = manager.document.GetLineByOffset(EndOffset.CoerceValue(0, manager.document.TextLength));
			if (startLine == endLine) {
				RemoveCollapsedLineSection();
			} else {
				if (collapsedSections == null)
					collapsedSections = new CollapsedLineSection[manager.textViews.Count];
				// Validate collapsed line sections
				DocumentLine startLinePlusOne = startLine.NextLine;
				for (int i = 0; i < collapsedSections.Length; i++) {
					var collapsedSection = collapsedSections[i];
					if (collapsedSection == null || collapsedSection.Start != startLinePlusOne || collapsedSection.End != endLine) {
						// recreate this collapsed section
						if (collapsedSection != null) {
							Debug.WriteLine("CollapsedLineSection validation - recreate collapsed section from " + startLinePlusOne + " to " + endLine);
							collapsedSection.Uncollapse();
						}
						collapsedSections[i] = manager.textViews[i].CollapseLines(startLinePlusOne, endLine);
					}
				}
			}
		}
		
		/// <inheritdoc/>
		protected override void OnSegmentChanged()
		{
			ValidateCollapsedLineSections();
			base.OnSegmentChanged();
			// don't redraw if the FoldingSection wasn't added to the FoldingManager's collection yet
			if (IsConnectedToCollection)
				manager.Redraw(this);
		}
		
		/// <summary>
		/// Gets/Sets the text used to display the collapsed version of the folding section.
		/// </summary>
		public string Title {
			get {
				return title;
			}
			set {
				if (title != value) {
					title = value;
					if (this.IsFolded)
						manager.Redraw(this);
				}
			}
		}
		
		/// <summary>
		/// Gets the content of the collapsed lines as text.
		/// </summary>
		public string TextContent {
			get {
				return manager.document.GetText(StartOffset, EndOffset - StartOffset);
			}
		}
		
		/// <summary>
		/// Gets the content of the collapsed lines as tooltip text.
		/// </summary>
		[Obsolete]
		public string TooltipText {
			get {
				// This fixes SD-1394:
				// Each line is checked for leading indentation whitespaces. If
				// a line has the same or more indentation than the first line,
				// it is reduced. If a line is less indented than the first line
				// the indentation is removed completely.
				//
				// See the following example:
				// 	line 1
				// 		line 2
				// 			line 3
				//  line 4
				//
				// is reduced to:
				// line 1
				// 	line 2
				// 		line 3
				// line 4
				
				var startLine = manager.document.GetLineByOffset(StartOffset);
				var endLine = manager.document.GetLineByOffset(EndOffset);
				var builder = new StringBuilder();
				
				var current = startLine;
				ISegment startIndent = TextUtilities.GetLeadingWhitespace(manager.document, startLine);
				
				while (current != endLine.NextLine) {
					ISegment currentIndent = TextUtilities.GetLeadingWhitespace(manager.document, current);
					
					if (current == startLine && current == endLine)
						builder.Append(manager.document.GetText(StartOffset, EndOffset - StartOffset));
					else if (current == startLine) {
						if (current.EndOffset - StartOffset > 0)
							builder.AppendLine(manager.document.GetText(StartOffset, current.EndOffset - StartOffset).TrimStart());
					} else if (current == endLine) {
						if (startIndent.Length <= currentIndent.Length)
							builder.Append(manager.document.GetText(current.Offset + startIndent.Length, EndOffset - current.Offset - startIndent.Length));
						else
							builder.Append(manager.document.GetText(current.Offset + currentIndent.Length, EndOffset - current.Offset - currentIndent.Length));
					} else {
						if (startIndent.Length <= currentIndent.Length)
							builder.AppendLine(manager.document.GetText(current.Offset + startIndent.Length, current.Length - startIndent.Length));
						else
							builder.AppendLine(manager.document.GetText(current.Offset + currentIndent.Length, current.Length - currentIndent.Length));
					}
					
					current = current.NextLine;
				}
				
				return builder.ToString();
			}
		}
		
		/// <summary>
		/// Gets/Sets an additional object associated with this folding section.
		/// </summary>
		public object Tag { get; set; }
		
		internal FoldingSection(FoldingManager manager, int startOffset, int endOffset)
		{
			Debug.Assert(manager != null);
			this.manager = manager;
			this.StartOffset = startOffset;
			this.Length = endOffset - startOffset;
		}
		
		void RemoveCollapsedLineSection()
		{
			if (collapsedSections != null) {
				foreach (var collapsedSection in collapsedSections) {
					if (collapsedSection != null && collapsedSection.Start != null)
						collapsedSection.Uncollapse();
				}
				collapsedSections = null;
			}
		}
	}
}

s="n">DocumentLine line = document.GetLineByNumber(lineNumber);
				highlightedLine = new HighlightedLine(document, line);
				HighlightLineAndUpdateTreeList(line, lineNumber);
				return highlightedLine;
			} finally {
				highlightedLine = null;
				isHighlighting = false;
			}
		}
		
		/// <inheritdoc/>
		public SpanStack GetSpanStack(int lineNumber)
		{
			ThrowUtil.CheckInRangeInclusive(lineNumber, "lineNumber", 0, document.LineCount);
			if (firstInvalidLine <= lineNumber) {
				CheckIsHighlighting();
				isHighlighting = true;
				try {
					HighlightUpTo(lineNumber + 1);
				} finally {
					isHighlighting = false;
				}
			}
			return storedSpanStacks[lineNumber];
		}
		
		void CheckIsHighlighting()
		{
			if (isHighlighting) {
				throw new InvalidOperationException("Invalid call - a highlighting operation is currently running.");
			}
		}
		
		void HighlightUpTo(int targetLineNumber)
		{
			Debug.Assert(highlightedLine == null); // ensure this method is only used for
			while (firstInvalidLine < targetLineNumber) {
				HighlightLineAndUpdateTreeList(document.GetLineByNumber(firstInvalidLine), firstInvalidLine);
			}
		}
		
		void HighlightLineAndUpdateTreeList(DocumentLine line, int lineNumber)
		{
			//Debug.WriteLine("Highlight line " + lineNumber + (highlightedLine != null ? "" : " (span stack only)"));
			spanStack = storedSpanStacks[lineNumber - 1];
			HighlightLineInternal(line);
			if (!EqualSpanStacks(spanStack, storedSpanStacks[lineNumber])) {
				isValid[lineNumber] = true;
				//Debug.WriteLine("Span stack in line " + lineNumber + " changed from " + storedSpanStacks[lineNumber] + " to " + spanStack);
				storedSpanStacks[lineNumber] = spanStack;
				if (lineNumber + 1 < isValid.Count) {
					isValid[lineNumber + 1] = false;
					firstInvalidLine = lineNumber + 1;
				} else {
					firstInvalidLine = int.MaxValue;
				}
				OnHighlightStateChanged(line, lineNumber);
			} else if (firstInvalidLine == lineNumber) {
				isValid[lineNumber] = true;
				firstInvalidLine = isValid.IndexOf(false);
				if (firstInvalidLine < 0)
					firstInvalidLine = int.MaxValue;
			}
		}
		
		static bool EqualSpanStacks(SpanStack a, SpanStack b)
		{
			// We must use value equality between the stacks because TextViewDocumentHighlighter.OnHighlightStateChanged
			// depends on the fact that equal input state + unchanged line contents produce equal output state.
			if (a == b)
				return true;
			if (a == null || b == null)
				return false;
			while (!a.IsEmpty && !b.IsEmpty) {
				if (a.Peek() != b.Peek())
					return false;
				a = a.Pop();
				b = b.Pop();
				if (a == b)
					return true;
			}
			return a.IsEmpty && b.IsEmpty;
		}
		
		/// <summary>
		/// Is called when the highlighting state at the end of the specified line has changed.
		/// </summary>
		/// <remarks>This callback must not call HighlightLine or InvalidateHighlighting.
		/// It may call GetSpanStack, but only for the changed line and lines above.
		/// This method must not modify the document.</remarks>
		protected virtual void OnHighlightStateChanged(DocumentLine line, int lineNumber)
		{
		}
		
		#region Highlighting Engine
		SpanStack spanStack;
		
		// local variables from HighlightLineInternal (are member because they are accessed by HighlighLine helper methods)
		string lineText;
		int lineStartOffset;
		int position;
		
		/// <summary>
		/// the HighlightedLine where highlighting output is being written to.
		/// if this variable is null, nothing is highlighted and only the span state is updated
		/// </summary>
		HighlightedLine highlightedLine;
		
		void HighlightLineInternal(DocumentLine line)
		{
			lineStartOffset = line.Offset;
			lineText = document.GetText(line.Offset, line.Length);
			position = 0;
			ResetColorStack();
			HighlightingRuleSet currentRuleSet = this.CurrentRuleSet;
			Stack<Match[]> storedMatchArrays = new Stack<Match[]>();
			Match[] matches = AllocateMatchArray(currentRuleSet.Spans.Count);
			Match endSpanMatch = null;
			
			while (true) {
				for (int i = 0; i < matches.Length; i++) {
					if (matches[i] == null || (matches[i].Success && matches[i].Index < position))
						matches[i] = currentRuleSet.Spans[i].StartExpression.Match(lineText, position);
				}
				if (endSpanMatch == null && !spanStack.IsEmpty)
					endSpanMatch = spanStack.Peek().EndExpression.Match(lineText, position);
				
				Match firstMatch = Minimum(matches, endSpanMatch);
				if (firstMatch == null)
					break;
				
				HighlightNonSpans(firstMatch.Index);
				
				Debug.Assert(position == firstMatch.Index);
				
				if (firstMatch == endSpanMatch) {
					HighlightingSpan poppedSpan = spanStack.Peek();
					if (!poppedSpan.SpanColorIncludesEnd)
						PopColor(); // pop SpanColor
					PushColor(poppedSpan.EndColor);
					position = firstMatch.Index + firstMatch.Length;
					PopColor(); // pop EndColor
					if (poppedSpan.SpanColorIncludesEnd)
						PopColor(); // pop SpanColor
					spanStack = spanStack.Pop();
					currentRuleSet = this.CurrentRuleSet;
					//FreeMatchArray(matches);
					if (storedMatchArrays.Count > 0) {
						matches = storedMatchArrays.Pop();
						int index = currentRuleSet.Spans.IndexOf(poppedSpan);
						Debug.Assert(index >= 0 && index < matches.Length);
						if (matches[index].Index == position) {
							throw new InvalidOperationException(
								"A highlighting span matched 0 characters, which would cause an endless loop.\n" +
								"Change the highlighting definition so that either the start or the end regex matches at least one character.\n" +
								"Start regex: " + poppedSpan.StartExpression + "\n" +
								"End regex: " + poppedSpan.EndExpression);
						}
					} else {
						matches = AllocateMatchArray(currentRuleSet.Spans.Count);
					}
				} else {
					int index = Array.IndexOf(matches, firstMatch);
					Debug.Assert(index >= 0);
					HighlightingSpan newSpan = currentRuleSet.Spans[index];
					spanStack = spanStack.Push(newSpan);
					currentRuleSet = this.CurrentRuleSet;
					storedMatchArrays.Push(matches);
					matches = AllocateMatchArray(currentRuleSet.Spans.Count);
					if (newSpan.SpanColorIncludesStart)
						PushColor(newSpan.SpanColor);
					PushColor(newSpan.StartColor);
					position = firstMatch.Index + firstMatch.Length;
					PopColor();
					if (!newSpan.SpanColorIncludesStart)
						PushColor(newSpan.SpanColor);
				}
				endSpanMatch = null;
			}
			HighlightNonSpans(line.Length);
			
			PopAllColors();
		}
		
		void HighlightNonSpans(int until)
		{
			Debug.Assert(position <= until);
			if (position == until)
				return;
			if (highlightedLine != null) {
				IList<HighlightingRule> rules = CurrentRuleSet.Rules;
				Match[] matches = AllocateMatchArray(rules.Count);
				while (true) {
					for (int i = 0; i < matches.Length; i++) {
						if (matches[i] == null || (matches[i].Success && matches[i].Index < position))
							matches[i] = rules[i].Regex.Match(lineText, position, until - position);
					}
					Match firstMatch = Minimum(matches, null);
					if (firstMatch == null)
						break;
					
					position = firstMatch.Index;
					int ruleIndex = Array.IndexOf(matches, firstMatch);
					if (firstMatch.Length == 0) {
						throw new InvalidOperationException(
							"A highlighting rule matched 0 characters, which would cause an endless loop.\n" +
							"Change the highlighting definition so that the rule matches at least one character.\n" +
							"Regex: " + rules[ruleIndex].Regex);
					}
					PushColor(rules[ruleIndex].Color);
					position = firstMatch.Index + firstMatch.Length;
					PopColor();
				}
				//FreeMatchArray(matches);
			}
			position = until;
		}
		
		static readonly HighlightingRuleSet emptyRuleSet = new HighlightingRuleSet() { Name = "EmptyRuleSet" };
		
		HighlightingRuleSet CurrentRuleSet {
			get {
				if (spanStack.IsEmpty)
					return baseRuleSet;
				else
					return spanStack.Peek().RuleSet ?? emptyRuleSet;
			}
		}
		#endregion
		
		#region Color Stack Management
		Stack<HighlightedSection> highlightedSectionStack;
		HighlightedSection lastPoppedSection;
		
		void ResetColorStack()
		{
			Debug.Assert(position == 0);
			lastPoppedSection = null;
			if (highlightedLine == null) {
				highlightedSectionStack = null;
			} else {
				highlightedSectionStack = new Stack<HighlightedSection>();
				foreach (HighlightingSpan span in spanStack.Reverse()) {
					PushColor(span.SpanColor);
				}
			}
		}
		
		void PushColor(HighlightingColor color)
		{
			if (highlightedLine == null)
				return;
			if (color == null) {
				highlightedSectionStack.Push(null);
			} else if (lastPoppedSection != null && lastPoppedSection.Color == color
			           && lastPoppedSection.Offset + lastPoppedSection.Length == position + lineStartOffset)
			{
				highlightedSectionStack.Push(lastPoppedSection);
				lastPoppedSection = null;
			} else {
				HighlightedSection hs = new HighlightedSection {
					Offset = position + lineStartOffset,
					Color = color
				};
				highlightedLine.Sections.Add(hs);
				highlightedSectionStack.Push(hs);
				lastPoppedSection = null;
			}
		}
		
		void PopColor()
		{
			if (highlightedLine == null)
				return;
			HighlightedSection s = highlightedSectionStack.Pop();
			if (s != null) {
				s.Length = (position + lineStartOffset) - s.Offset;
				if (s.Length == 0)
					highlightedLine.Sections.Remove(s);
				else
					lastPoppedSection = s;
			}
		}
		
		void PopAllColors()
		{
			if (highlightedSectionStack != null) {
				while (highlightedSectionStack.Count > 0)
					PopColor();
			}
		}
		#endregion
		
		#region Match helpers
		/// <summary>
		/// Returns the first match from the array or endSpanMatch.
		/// </summary>
		static Match Minimum(Match[] arr, Match endSpanMatch)
		{
			Match min = null;
			foreach (Match v in arr) {
				if (v.Success && (min == null || v.Index < min.Index))
					min = v;
			}
			if (endSpanMatch != null && endSpanMatch.Success && (min == null || endSpanMatch.Index < min.Index))
				return endSpanMatch;
			else
				return min;
		}
		
		static Match[] AllocateMatchArray(int count)
		{
			if (count == 0)
				return Empty<Match>.Array;
			else
				return new Match[count];
		}
		#endregion
	}
}